FIG. 1 is a block diagram showing an arrangement of a conventional onboard device abnormal connection notification system as disclosed in JP-A 7-160955(1995). In the figure, reference numeral 101 denotes an audio visual (AV) source, reference numeral 102 denotes an alarm control apparatus, reference numeral 103 denotes a liquid crystal projector main body, reference numeral 104 denotes an alarm apparatus, reference numeral 105 denotes an audio cable, reference numeral 106 denotes a video cable, reference numeral 107 denotes a power cable from a battery, reference numeral 108 denotes a power cable to the liquid crystal projector main body 103, reference numeral 109 denotes an audio cable and reference numeral 110 denotes a multicore cable for supplying a video signal and a theft-detecting signal.
For example, should the liquid crystal projector main body 103 be attempted to be removed, the multicore cable 110 will also be cut off. Therefore, the alarm control apparatus 102 detects the abnormality and orders the alarm apparatus 104 to give an alarm based on the theft-detecting signal, whereby the alarm apparatus 104 sounds an alarm.
FIG. 2 is a schematic diagram showing an arrangement of a conventional onboard device abnormal connection notification system as disclosed in JP-A 8-268182(1996). In the figure, reference numeral 121 denotes a car audio main body, reference numeral 122 denotes a unit for a security apparatus, reference numeral 123 denotes an audio nose piece formed in a manner detachable relative to a front surface of the car audio main body 121 and reference numeral 124 denotes a similarly formed security nose piece. The audio nose piece 123 and the security nose piece 124 are constructed to be interchangeably mounted relative to the front surface of the car audio main body 121.
When a user of the motor vehicle leaves the motor vehicle, the audio nose piece 123 is detached and the security nose piece 124 is attached to the car audio main body 121. Should the door of the motor vehicle be forcibly opened, or a windshield thereof be broken, a sensor disposed in the security nose piece 124 detects the abnormality. The unit 122 for the security apparatus then sounds a siren to thereby perform theft-deterring of the onboard devices and the motor vehicle.
FIG. 3 is a perspective structural view showing an arrangement of a conventional theft-deterring system for onboard devices as disclosed in JP-A 9-330487(1997). In the figure, reference numeral 131 denotes a fixed panel. A smoked plate 132 is adhered to this fixed panel 131, and the entire front surface of an operation panel is covered by this smoked plate 132. On the rear side of this smoked panel 132, a display tube 134 mounted on a substrate 133 is disposed. On one side of the substrate 133 there are disposed a photo element 135 and a light-emitting diode (LED) 136.
By setting the smoked plate 132 slightly darker, when an ACC (accessory) which is the position of key to the motor vehicle is OFF, the display (segment or the like) of the display tube 134 on the inner side is hardly visible from the outside. It is thus possible to make believe at a glance that it does not function as an audio device. When the ACC of the motor vehicle is switched on, the display tube 134 emits light so as to become visible even through the smoked plate 132, whereby the user can see the display. In this manner, the theft-deterring is intended by causing the audio device invisible to the outside when the user leaves the motor vehicle.
As described in each of the above conventional examples, in the conventional onboard device abnormal connection notification system or in the conventional theft-deterring system, an abnormal connection notification or a theft-deterring is performed for each of the onboard devices.
However, recently, various types of onboard devices are offered such as not only audio devices but also navigation devices, television sets, car personal computers, or the like. As a result, the kinds of onboard devices available for use inside a motor vehicle increase.
Since the conventional onboard device abnormal connection notification or the theft-deterring system is arranged as described above, there are problems in that the cost becomes expensive because the abnormal connection notification systems or a theft-deterring systems are installed for respective onboard devices and further that a new abnormal connection notification system or a theft-deterring system is required when a new onboard device is to be installed, resulting in a waste.
This invention has been made to solve the above problems and has an object of providing an onboard device abnormal connection notification system as well as an onboard device which are capable of notifying a connection abnormality to a plurality of onboard devices with a single system and which are capable of being adapted when an onboard device is newly installed.